The silent world into which thousands of divers have been slipping excitedly for the past 10 years is now humming with the soft throb of propellers. To travel further and more easily than they could ever hope to on flippered feet, sportsmen now strap on pedal-driven propellers or, in the tow of surface craft, literally soar through the water five miles an hour on undersea sleds. In small, two-man submarines, evolved from the midget subs which menaced shipping in World War II, divers can now cruise more than 25 miles without refueling. Figuring that the simplest way to enjoy the vast world in which he had been prowling for 20 years would be to ride on a sting ray, Peter Stack-pole, the LIFE photographer, this month perfected a mechanical sting ray. Using this new propeller-driven underwater wing (below), sportsmen will be able to dive and glide tirelessly three miles an hour. How do the fish react to this new underwater traffic? Diver Stackpole and other riders of the deep report that the fish generally yield the right of way, but beyond that not even the queerest fish pays much attention to these odd new creations in the sea.

Underwater wing designed by Stackpole uses rechargeable one-hour batteries and, since riding is effortless, enables diver to go up to 50% farther on his air supply.

Sportsman's submarine, a two-man gas-powered version of the Italian midget subs which crippled or sank a dozen ships during war, has cruising range of 25 miles.

On undersea sled towed by a surface boat two divers careen through the Gulf Stream. Since sleds are very maneuverable, divers find them ideal for tracking fish.